@Kelly Maas look at the green shaded region of ear.

Please check zenbud which is using this area. The neck seems to be risky.

It is believed that lower intensity is better for VNS. There is certainly a goldilock range. Higher intensity causes inhibition of vagus conduction. That is bad if you want to increase excitation. However, if you want to suppress conduction (may be in over active situations), it could make sense.

I think lower intensity is better. Based on a study I read, we will benefit from lower intensity. // Ultrasound neuromodulation can produce either inhibition or excitation depending on parameters like intensity, frequency, duty cycle, and duration—low intensities often excite via mechanical ion channel effects, while higher ones inhibit via thermal disruption. The study’s high intensities favored inhibition, but later vagus ultrasound works use lower parameters to achieve excitatory, therapeutic outcomes like reduced inflammation, heart rate lowering, or motor recovery without blocking conduction.